This invention relates to a system for emplacing a prosthesis and, more particularly, to a catheter system for placement of a graft having attachment means within a corporeal lumen.
It is well established that various fluid conducting body or corporeal lumens, such as veins and arteries, may deteriorate or suffer trauma so that repair is necessary. For example, various types of aneurysms or other deteriorative diseases may affect the ability of the lumen to conduct fluids and in turn may be life-threatening. In some cases, the damaged lumen is repairable only with the use of prosthesis such as an artificial vessel or graft.
For repair of vital vessels such as the aorta, surgical repair is significantly life-threatening. Surgical techniques known in the art involve major surgery in which a graft resembling the natural vessel is spliced into the diseased or obstructed section of the natural vessel. Known procedures include surgically removing or bypassing the damaged or diseased portion of the vessel and inserting an artificial or donor graft inserted and stitched to the ends of the vessel which were created by the removal of the diseased portion.
It is known within the art to provide a prothesis for intraluminal repair of a vessel, such as an abdominal aorta having an aneurysm. The art has taught to provide a prothesis positioned in a vessel then securing the prothesis within the vessel with hooks or staples that are mechanically extended by the user. The early prior art devices were large in diameter, mechanically complex and in turn were susceptible to mechanical failure. Prior intraluminal grafting systems have embodied capsule catheters or balloon catheters, but were relatively stiff and of a relatively high profile. Similarly, the prior art systems were configured in such a way that the graft was relatively difficult to deploy the prothesis. In addition, prior systems having capsule catheter means were usually configured such that the prothesis was disposed within a unitary capsule.
In recent years, several devices have been developed to attempt to treat an aortic aneurysm through intraluminal repair. For example, U.S. Pat. No. 4,140,126 (Feb. 20, 1979), Choudhury, discloses a method and article for performing an aneurysm repair, wherein a prosthetic graft is utilized to replace the damaged segment of the blood vessel. A plurality of radially spaced anchoring pins are located adjacent each end of the graft and provide means for securing the graft to the wall of the vessel. Means is provided for moving the graft within the vessel and permanently anchoring the graft to the wall of the vessel.
U.S. Pat. No. 4,562,596 (Jan. 7, 1986), Kornberg, discloses a bifurcated aortic graft constructed for intraluminal insertion having a plurality of struts having angled hooks with barbs at their superior ends. Means for inserting the graft and implanting the hooks into the vessel lumen is also disclosed.
U.S. Pat. No. 4,787,899 (Nov. 29, 1988), Lazarus, discloses an intraluminal grafting system including a hollow graft having an attachment-means located at one end of the graft. The system includes positioning means for moving the graft within the vessel, the positioning means having a capsule positioned at one end for covering the graft attachment means. The disclosed positioning means further includes an inflatable member for securing the attachment means within the lumen.
EPO Pub. No. 0 461 791 A1 (Dec. 18, 1991), Barone et al. discloses an aortic graft and apparatus for repairing an aneurism. The disclosed system includes a tube graft secured within the aorta and an attachment means at each end of the graft. Intraluminal delivery is accomplished using a catheter having a balloon for expanding and securing the attachment means. The graft and attachment means are preferably enclosed by a sheath which covers the entire graft and attachment means.
EPO Pub. No. 0 466 518 A3 (Jan. 15, 1992), Lazarus et al., discloses an intraluminal grafting system including a catheter having a capsule formed of a helical wrap of metal ribbon. A tubular graft having attachment means at both ends is removably disposed within the capsule. Means is provided for moving the graft from the capsule, and an inflatable member is provided for securing the attachment means within a vessel lumen.
U.S. Pat. No. 5,104,399 (Apr. 14, 1992), Lazarus, discloses an intraluminal grafting system including a tubular graft having attachment means positioned at both ends. The system includes a positioning means for transporting the graft through a vessel lumen and for deploying the graft within the lumen. The positioning means includes an inflatable member, a capsule and means for removing the graft from the capsule. The capsule is disclosed as a rigid cylindrical member covering the entire graft.
EPO Pub. No. 0 508 473 A2 (Oct. 14, 1992), Piplani et al., discloses an intraluminal grafting system including a catheter having a capsule formed of a helical wrap of metal ribbon. A bifurcated graft having attachment means is removably disposed within the capsule. Means is provided for moving the graft from the capsule, and an inflatable member is provided for securing the attachment means within a vessel lumen.
The foregoing patents and publications are incorporated herein by reference.
To provide consistency with the common usage of terms used in the medical surgical arts in the United States, the terms xe2x80x9cproximal, distal, inferior and superiorxe2x80x9d are used with a certain regularity within the present specification. Proximal refers to parts of the system, such as catheters, capsules and wires, which are closest to the user and closest to the portion of the system outside or exterior of the patient. Distal refers to the point farthest from the user and typically most interior to the corporeal lumen. The term superior refers to a location situated above and is used herein in description of the graft and attachment means. Inferior refers to the point situated below and again is used herein with the graft and attachment means. Thus, for applications in the abdominal aorta which use a femoral approach, the superior end of the graft resides within the most distal portion of the balloon catheter. Likewise, the inferior end of the graft resides within the proximal capsule which is on the most distal portion of the capsule catheter.
In general, it is an object of the present invention to provide an intraluminal grafting system and method which overcome the disadvantages of the prior art systems.
The present system has several advantages over prior art systems. For example, the over the wire configuration of the balloon catheter enables traversing the aneurysm with a guidewire. Using a guidewire in this manner minimizes the risk of dislodging thrombus in the aneurysm, since the placement means follows the guidewire thereby preventing the distal tip from contacting the vessel wall. In addition, using a guidewire allows for traversing more difficult anatomy. Also, the guide wire lumen may function as a through lumen for real time angiograms during the emplacement procedure or to insert intravascular probes such as intravascular ultrasound systems.
As another advantage, the smaller diameter and lower profile of the capsule assemblies of the present invention permit use of the invention in a larger patient population because the variances in iliac vessel diameter. Similarly, the smaller device diameter relative to the iliac diameter may allow for easier navigation inside the corporeal lumen especially with more difficult anatomy. Likewise, the two capsule segments of the present invention permit a wider range of graft lengths than available with a single capsule design. The single capsule systems also require capsules slightly longer than the graft, which imposes certain manufacturing and deployment problems. Moreover, the shorter capsule segments provide a more flexible device, thereby allowing traversing more difficult anatomy.
The present invention comprises an intraluminal placement means for securing a prothesis within or between vessels or corporeal lumens of an animal, such as a human. The preferred embodiment of the placement means is configured for introducing a graft into a corporeal lumen and positioning the graft in the area of the aortic bifrucation. The placement means includes a balloon catheter, a capsule catheter and a capsule jacket. In the preferred embodiment, the balloon catheter and capsule catheter include capsule means for retaining the graft, including a proximal capsule means and a distal capsule means. The capsule means are movable relative to each other to allow the graft to be emplaced at the desired location in the corporeal lumen.
Preferably, the placement means includes a balloon catheter having a multilumen hollow tube or shaft having a proximal end provided with means for accepting a guide wire and with means for inflating a balloon or similar inflatable member. The balloon catheter shaft is of sufficient length that the proximal end remains exterior the corporeal lumen while the distal end of the balloon catheter shaft may be positioned proximate the portion of the corporeal lumen to be repaired. The balloon catheter further has means for inflating and deflating the balloon. In addition, the balloon catheter is coupled to control means and a distal capsule for retaining and releasing the superior end of the graft. In the preferred embodiment, the control means includes a control wire and handle mechanism which provides movement of the distal capsule relative to the balloon catheter shaft.
The placement means also includes a capsule catheter shaped and sized for positioning within the corporeal lumen. The capsule catheter comprises a hollow tube or shaft slidably mounted on the balloon catheter shaft, having a proximal end exterior the corporeal lumen for manipulation by the user. The capsule catheter includes a proximal capsule secured to the distal end of the capsule catheter shaft for retaining the inferior end of the graft. The placement means is configured to provide relative movement between the proximal capsule of the capsule catheter and the distal capsule of the balloon catheter for removing the graft from the capsule means and for subsequently urging the attachment means into engagement with the wall of the corporeal lumen.
The placement means further includes a capsule jacket for providing a smooth transition between the parts of the balloon catheter and capsule catheter. The capsule jacket comprises a double walled jacket or sheath configured coaxially with the balloon catheter and capsule catheter, having a proximal end exterior the corporeal lumen for manipulation by the user. The distal end of the capsule jacket flares outwardly to a size which is slidably retained over the distal capsule when the placement means in deployed into the corporeal lumen.
The present invention includes a prosthesis or graft for intraluminal placement in a fluid conducting corporeal lumen. For most applications the prothesis is a hollow graft of preselected cross-section and length. The graft is deformable to conform substantially to the interior surface of the corporeal lumen or other body part to be repaired. Preferably, the graft is made of a material suitable for permanent placement in the body such as polytetrafluroethylene or a polyester. During emplacement, the superior and inferior ends of the graft are positioned within the corporeal lumen and the graft is configured such that the graft traverses the diseased or damaged portion of the vessel. To anchor the graft to the wall of the corporeal lumen, attachment means are secured to the superior and inferior ends of the graft.
The preferred attachment means has wall engaging members. The wall engaging members of the superior attachment means are angled toward the inferior end of the graft. Similarly, the wall engaging members of the inferior attachment means are angled slightly toward the superior end of the graft. The wall engaging members of both attachment means have sharp tips for engaging the corporeal lumen wall. The preferred attachment means are formed into a V-shaped lattice or framework. The frame of the attachment means allows for elastic radial deformation resulting in a spring-like effect when a compressed attachment means is allowed to expand as the graft is released from the capsule means. In addition, radiopaque markers are secured to the longitudinal axis of the graft to facilitate orientation of the graft using fluoroscopy or x-ray techniques.
Deployment of the graft comprises a series of steps which begins with introducing the placement means into the corporeal lumen using well known surgical techniques. As a single system, the balloon catheter, capsule catheter and capsule jacket are manipulated to position the capsule means containing the graft and attachment means to a desired location within the corporeal lumen. Once the graft is in the desired location, the capsule jacket is withdrawn to expose the distal capsule and a portion of the graft. The distal capsule is then moved relative to the balloon catheter shaft and capsule catheter to expose the superior attachment means.
After the superior portion of the graft is removed from the capsule means, the inflatable member is moved to within the circumference of the superior attachment means and inflated to urge wall engaging members into the wall of the corporeal lumen. The capsule jacket and capsule catheter are then moved relative to the graft and balloon catheter shaft to expose the inferior attachment means. The balloon catheter shaft is then moved to position the inflatable member proximate the inferior attachment means. The inflatable member is then expanded to seat the wall engaging members of the inferior attachment means. The placement means is then removed from the corporeal lumen.
Other features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.